Scott Gilbert (Swarthmore College) and Ziony Zevit (American Jewish University) make the bold claim in their article, which appeared in the American Journal of Medical Genetics in 2001, that Adam’s baculum, rather than his rib, was the bone used to create Eve. They add:

Another genetic condition, extending to 100 percent of human males, is the congenital lack of a baculum. Whereas most mammals (including common species such as dogs and mice) and most other primates (excepting spider monkeys) have a penile bone, human males lack this bone and must rely on fluid hydraulics to maintain erections. This is not an insignificant bone. The baculum of a large dog can be 10 cm long x 1.3 cm wide x 1 cm thick… Human bacula have been reported, usually in association with other congenital diseases or penile abnormalities.

One of the central parts of the authors’ argument is that the Hebrew word used in Genesis 2:21, tzeilah, can refer not only to a rib (of which the professors point out there are an equal number in modern-day man, which ought to preclude the removal of just one of Adam’s ribs), but also:

the rib of a hill (2 Samuel 16:13), the side chambers (enclosing the temple like ribs, as in 1 Kings 6:5,6), or the supporting columns of trees, like cedars or firs, or the planks in buildings and doors (1 Kings 6:15,16). So the word could be used to indicate a structural support beam. Interestingly, Biblical Hebrew, unlike later rabbinic Hebrew, had no technical term for the penis and referred to it through many circumlocutions.

Although there is no technical term in the Old Testament for penis, there are verses that come close (like Deuteronomy 23:2). One wonders why the story about Adam didn’t use a similar euphemism.

The best part of the authors’ argument is their re-reading of the Genesis verse, “The Lord God closed up the flesh.” This “closing up,” they say, explains

the peculiar visible sign on the penis and scrotum of human males—the raphé . In the human penis and scrotum, the edges of the urogenital folds come together over the urogenital sinus (urethral groove) to form a seam, the raphé. If this seam does not form, hypospadias of the glans, penis, and scrotum can result. The origin of this seam on the external genitalia was “explained” by the story of the closing of Adam’s flesh. Again, the wound associated with the generation of Eve is connected to Adam’s penis and not his rib.

However inventive that interpretation is, however, it still doesn’t fit with the first half of the sentence. God didn’t take a tzeilah; he took “one of Adam’s tzeilot.” Unless the authors can explain what happened to all of Adam’s other bacula, their argument may not hold water, so to speak.